Echelon LNS Plug-in - Manual (Page 41)

After creating an instance of a plug-in, the director can set any property at any time, with the exception
that the NetworkInterfaceName property, which if set, must be set before the NetworkName
property.
Uninstallation Issues
Your plug-in should implement the LcaCommandUnregister (51) command for LNS network
databases in order to allow de-registration of plug-in function from individual network databases,
while still providing the plug-in functionality on the computer.
If an LNS device plug-in needs to be uninstalled, the LNS plug-in registration data in the Windows
registry may need to be removed before the COM server registration, so that the COM server will be
able to perform the plug-in de-registration.
After running the uninstall program (and deleting the registration data in the Windows registry as
described above), the LNS device plug-in is properly uninstalled from a Windows operating system
point of view.
After Windows uninstallation, within one or more LNS databases, there may be ComponentApp
objects that refer to this now-uninstalled plug-in. An LNS director may choose to remove the
ComponentApp references to an LNS device plug-in within an LNS database if it determines that the
plug-in has been uninstalled from the computer. If these references are not removed, a director will get
a COM exception when it attempts to launch the now uninstalled plug-in and can display an
appropriate error message to the user. Because the plug-in software un-installation process is
independent from any individual LNS network database access, plug-in directors should implement
either automatic or user-specified clean-up when ComponentApp references to non-existent plug-ins
are encountered.
Generally, uninstalling a plug-in should not remove manufacturer resource files because other devices
from the manufacturer may use these.